Motor with pump and blower for oil burners

ABSTRACT

THE INVENTION RELATES TO A MOTORIZED PUMP AND BLOWER ASSEMBLY FOR OIL BURNERS. THE MOTOR ROTOR IS DIVIDED INTO TWO PARTS WITH ONE ROTOR PART FOR DRIVING THE PUMP BEING INTERNALLY OF THE STATOR AND THE OTHER ROTOR PART FOR DRIVING THE   BLOWER BEING EXTERNALLY OF THE STATOR. THE ASSEMBLY HOUSING IS PROVIDED WITH BEARING AND JOURNAL MEANS ON OPPOSITE SIDES OF THE STATOR FOR ROTATABLY SUPPORTING THE TWO ROTOR PARTS.

United States Patent Inventors Leif V. Sturlason Sonderborg; Kym G. Sjotun, Langeso PR. Nordborg, Denmark Appl. No. 827,604 Filed May 26, 1969 Patented June 28, 1971 Assignee Daufoss A/S Nordborg, Denmark Priority May 21, 1968 Germany 2 17 51 388.1

MOTOR WITH PUMP AND BLOWER FOR OIL BURNERS [50] Field of Search 310/67, 114,126, 266; 230/1 17, 44, 45; 103/5, 6; 417/410, 201

Primary Examiner-Robert M. Walker Attorney-Wayne B. Easton ABSTRACT: The invention relates to a motorized pump and blower assembly for oil burners. The motor rotor is divided 3 Claims 2 Drawing Figs into two parts with one rotor part for driving the pump being US. Cl. 417/201, internally of the stator and the other rotor part for driving the 417/410 blower being externally of the stator. The assembly housing is Int. Cl ..F04b 13/02, provided with bearing and journal means on opposite sides of F04d 25/06 the stator for rotatably supporting the two rotor parts.

M ii l3 9 i I u T MOTOR WITH PUMP AND BLOWER FOR 01L BURNERS The invention relates to a motor with pump and blower for oil burners.

Normally a motor powers both the pump and the blower of the oil burner. When the motor is switched off trouble is caused by its not coming immediately to a stop. Oil continues to be fed in under diminishing pressure for a further period. To prevent this oil from dripping from the nozzle and becoming carbonized at that point, complicated cutoff valves are fitted between the pump and the nozzle, and these respond to the oil pressure for example and have to close in a jerky manner, as soon as the pressure drops below a predetermined value.

It has been proposed to divide the rotor into two parts, one of which drives the pump and the other the blower, the two functions being independent of each other, and both parts are disposed in an undivided stator. In this construction, the inert mass of the rotating parts connected to the pump is considerably reduced. The pump therefore comes to a stop more quickly. Consequently, less oil, that could continue to drip, is fed in after the motor has been switched off.

Conversely, the blower is no longer braked by the pump. It therefore continues to run for a considerably longer period. Consequently, oil dripping from the nozzle is blown away and still combusted, so that carbonization cannot occur. The switchingoff operation can therefore be controlled without a cutoff valve or with a cutoff valve of very simple design.

The object of the invention is to achieve the shortest possible pump rundown time and the longest possible blower rundown time, using an extremely simple construction.

According to the invention, this object is achieved by providing, in the stator, an inner rotor for driving the pump and an outer rotor'for driving the blower.

By means of this construction, not only is the axial length of the unit reduced, but the blower, due to the greater diameter of the outer rotor, has a greater moment of inertia and there fore a long slowdown time. The inner rotor, on the other hand, has a very small moment ofinertia and is also braked by the oil supplied by the pump, so that a very short rundown time results. Moreover, the outer rotor has a large starting moment, so that the blower starts up quickly. On the other hand, the inner rotor has a small starting moment and is more violently braked by the pump. Consequently, the full air capacity is available at the moment when oil is first fed into the combustion chamber.

It is particularly advantageous if the outer rotor is fitted with blower blades on its outer circumference. These blades, fitted on a component of relatively large diameter, provide a very good blowing effect.'lt is thus possible to dispense with a separate blower wheel coupled to the rotor.

It is also expedient to arrange the bearings for the inner rotor and the outer rotor on both sides of the stator and to interconnect them by way of retaining means extending between the two rotors. This results in a stable unit which can be attached to, for example, the housing carrying the bearing for the inner rotor and which, outside the blower, incorporates no elements impeding the movement of the delivered air.

It is also advantageous to use a sleeve which bears against the inner or outer circumference of the stator, is pushed on to the pump housing and, together with parts of the retaining means, encloses an oil chamber. The oil has a braking effect on the inner rotor, so that, after switching off, the pump comes to a stop still more quickly. Furthermore, the stuffing box between the pump and the oil chamber can be omitted, so that the pump shaft rotates with considerably less friction. The increased power thus obtainable more than covers, by a considerable extent, the losses due to the oil-braking. Finally, the oil in the oil chamber can also be used for cooling purposes.

A particularly advantageous construction is that wherein the sleeve is constituted by a part of a cup-shaped element, the base of which supports the bearing for the outer rotor.

The combining of the blower with the outer rotor enables a further simplification to be achieved in that the blower blades and the bearing support for the outer rotor can, together with the cage of this roto r be injection-molded as one iece.

The invention will now be described in grea er detail by reference to two embodiments illustrated in the drawing, in which:

FIG. 1 shows a longitudinal section through a first embodiment, and

FIG. 2 shows part of the longitudinal section of a second embodiment.

Referring to FIG. 1, a housing 1 is provided with a fixing flange 2. An oil pump 5 of standard construction is located in a cavity 3 at the end-face of the housing, which cavity is closed by a cover plate 4. The housing also carries a bearing 6 for the pump shaft 7. Also contained in the housing are feed pipes and valves which, for reasons of greater clarity, are not shown in the drawing.

An electric motor comprises a stator 8, which is secured to the housing 1, an inner rotor 9, mounted on the pump shaft 7, and an outer rotor 10, mounted on a fixed journal 14 by way of an endwall 11, a bearing support 12 and a bearing bush 13. The journal is secured in a wall-portion 15 which is fitted to the stator 8. The stator 8 and the wall-portion 15 therefore form a retaining means, which interconnects the bearings for the inner rotor and the outer rotor.

A sleeve 16 lies against the outer circumference of the stator 8 and is pushed on to a cylindrical part 18 of the housing 1, a ring 17 being used to provide a seal. Thus, the sleeve 16 and the wall-portion 15 form an oil chamber 19, in which the stator and the inner rotor 9 are contained. The sleeve 16 and the wall-portion 15 can also be made as one piece.

The laminations of the outer rotor 10 are contained in a housing 20 which carries the blower blades 21. The parts 20 and 21 and the endwall l1 and the bearing support 12 are formed as one piece.

When assembling the unit, the housing 1, the pump 5, the inner rotor 9 and the stator 8 are first fitted together. Then the sleeve 16 is pushed on and held in position by fitting the wallportion 15 on the stator 8. Finally the outer rotor 10 is pushed on to the journal 14 and secured in position there.

In the embodiment shown in FIG. 2, the same reference numcrals are used for like or similar parts. The important difference resides in the fact that, for connecting the two bearings 6 and 14, a cup-shaped element 22 is used, the circumferential face 23 of which replaces the sleeve 16 and lies against the inner circumference of the stator 8, and is pushed on to a cylindrical face 25 of the housing 1, a sealing ring 24 being interposed. The base 26 carries the journal 14. This results in a smaller oil chamber 27, which only contains the inner rotor 9.

In this form of construction, the short-circuiting ring 28 of the outer rotor and the entire cage (not visible), together with the parts l1, 12, 20 and 21 are injection-molded as one piece, these also replacing the short-cir'cuiting ring on the side opposite the ring 28.

We claim:

1. A motorized pump and blower assembly for oil burners comprising a housing, a stator fixed to said housing, a first rotor surrounded by said stator, a second rotor surrounding said stator, said rotors being rotatably mounted relative to said stator and independently of each other, pump means attached to said first rotor, blower blades attached to the periphery of said second rotor, and sleeve means attached to said stator and cooperable with said housing to form a fluid tight oil chamber enclosing said first rotor to provide hydraulic braking for said first rotor when said chamber is filled with oil.

2. An assembly according to claim 1 wherein said sleeve means bears against the outer periphery ofsaid stator.

3. An assembly according to claim 1 wherein said sleeve means bear against the inner periphery ofsaid stator. 

